A great example of this is the extension Sponsorblock. If you install it, it will only access data for the YouTube domain and YouTube nocookie domains. On the options page it allows us to specify more domains to allow it to access and only accesses those.
Discussion
Created GitHub feature requests for this for further discussion
https://github.com/diegogurpegui/nos2x-fox/issues/2
https://github.com/fiatjaf/nos2x/issues/22
https://github.com/getAlby/lightning-browser-extension/issues/1999